Requesting Advice from GRM Gods

So, i have removed the head on the Volvo, installed the new valve and started bolting everything back up. When i disassembled everything, i set everything to TDC as the directions tell me. With Volvos, the valve cover is two different pieces: Lower - for the cams, and upper - locks the cams into place. I re-align everything, crank is still at TDC, and the cams are the same. I put the timing belt on, tensioner on, and try to turn the crank one revolution. IT WONT BUDGE. The timing belt sounds like a rubber band going around a poster. Im not forcing anything, but it will not move!

I did the valve cover bolts that hold the cams in place at 15ft pounds, and the tensioner at 15 ft pounds. the belt and timing is aligned just as i had removed it. Im at a loss. Helpz pleeeze!

Pics for reference: Crank pulley is inline, as shown in this instructional pic.

the 2 yellow marks on the cams are lined up, yellow on the crank pulley is lined up, and a line on the harmonic balancer for good measure...

better pic

Spark plugs removed? Was everything that needed to be lubed lubed?

I have a spare head if need be. Off me wifes 93, 850 non turbo.

Sorry, have to ask. Is it a manual in gear?

vwcorvette wrote: Sorry, have to ask. Is it a manual in gear?

That's what I was going to say.

Hmmm. A tuff one.

Did you try turning the crank with the head off? If you did and it did and now it doesn't, then something happened when the head was reinstalled. Not moving even a bit sounds like a piston's hitting a valve, but on more than one cylinder.

Tha manual for my 907 Lotus engine (also a DOHC interference motor) says to turn the crank so the pistons are halfway down the cylinders before sticking the head back on. Only then do you turn the cams to their proper position, BEFORE installing the head, stick the head on and then GENTLY turn the crank to the proper spot. If you feel ANY resistance, you STOP and investigate.

In reply to mrhappy:

No plugs in it

In reply to vwcorvette:

in neutral

In reply to Jensenman:

i didnt move the crank while the head was off. I wanted to leave it as i left it.

I have not gone as deep into one of these motors, only the top half of the head (cam cover) off. When removing this the cams popped up due to the tension on the timing belt and pressure from the valve springs. Luckily someone has explained that this was going to happen before hand, otherwise I would have been pretty worried about what I had screwed up.

When bolting the cam cover back on, are you sure both cams went into the bearings with the correct alignment and that the lobes are contacting the buckets correctly? This would be a good first place to investigate as redoing the cam cover gasket is not too hard.

I am thinking all the cam lobes are correctly aligned. the cam seals are in the proper spots and everything is sealed up. I have looked everywhere for a torque spec for the cam cover, so i was doing them at 15 ft pounds. Dont know if that is too much or not.

Some engines have locking mechanisms built into their cam gears, or locking mechanisms which can be inserted into the cam gear to prevent them from moving. Does this have one? Did you leave it in?

Does the cylinder head involve any rotating path? Any oil pump drives, distributors or anything like that? Maybe you're looking in the wrong place for the gotcha.

You said you followed the directions-from where? Haynes manuals get things wrong from time to time. Did you use special tools? iirc thats the problem with that timing belt job-without some special tools you're fubar. I never owned one so I never investigated this.

followed off the Volvo-Forums. Have the tools as well.

Removed the timing belt. Rotate the cams by hand. find your problem.

DukeOfUndersteer wrote: followed off the Volvo-Forums. Have the tools as well.

Get a book, preferably factory, or other corroborating source that you're doing it right. I always take user-generated instructions with a grain of salt. Even if its not your problem a manual might help diagnose it.

iceracer wrote: Removed the timing belt. Rotate the cams by hand. find your problem.

I would modify this slightly to avoid the pain in the ass factor. Release the tension on the tensioner and wiggle each cam gear with its bolt. make sure each cam can move independently a few degrees. With the tensioner still released, wiggle crank and find out which one won't move. That way you don't have to take the belt off again.

took the tensioner back out, checked the play on the cams. The intake cam has good amount of movement, the exhaust cam is alittle stiffer. I only moved it about 2 degrees or so, just to see if they are moving. Did the same with the Crank, moving freely.

Well it sounds like something is mucking up the exhaust cam. What exactly did you do to this head? Install a valve? I'd check the valve itself that you touched. Why did you change the valve? Was something damaged which caused you to do this swap? If so, it may have damaged something you didn't expect, and even though the job went perfectly, the cam (or whatever) is still bent.

I assume it was an exhaust valve that you changed. I don't know how that valvetrain looks, but I guess I would try to take that valve actuation out of play to see if there is a noticeable difference. Perhaps the replacement valve is too long or something, perhaps there is an issue with the spring or something. Look there.

i changed an exhaust valve:

Well I really hate to be "that guy", but if you changed an exhaust valve, and now the exhaust cam is really tight, either you did it wrong or you broke something else when you broke the exhaust valve.

How did you break that, by the way?

break the valve free? Or how that damage occured? I bought it with it running on 4 of the 5 cylinders as this was the reason why there was no compression in one cylinder

DukeOfUndersteer wrote: break the valve free? Or how that damage occured? I bought it with it running on 4 of the 5 cylinders as this was the reason why there was no compression in one cylinder

I see. Then the PO broke it. Well, I would guess that they broke something else too, either that or you reassembled it incorrectly.

I think you'd have to know the circumstances under which it broke to do any real guesswork without going out there and looking at the valvetrain to decide what would make the engine harder to spin with a new, straight valve in there vs an old broken potentially bent one.

They make a special tool to torque the top half of the head evenly. It can be done without it if the bolts are torqued slowly and evenly. Might be the reason for the cam binding.

Also, they aren't supposed to be assembled at TDC. But the picture you posted looks like you have it at the correct mark. May have hit a valve on the piston

Cone_Junky wrote: They make a special tool to torque the top half of the head evenly. It can be done without it if the bolts are torqued slowly and evenly. Might be the reason for the cam binding. Also, they aren't supposed to be assembled at TDC. But the picture you posted looks like you have it at the correct mark. May have hit a valve on the piston

Assuming you have a spare set of head bolts, this hypothesis is easy enough to test, untorque it and try to rotate it loose.